Apparatus for casting metal



Sept. 5, 1950 Filed Sept. 13, 1947 H. w. GRAUSAM 2,52 1 ,362 APPARATUS FOR uswmc 1mm. Y

2 Sheets-Sheet 1 luvmvroa. Gra asa m Harold W HI'YWRNEYS.

Sept. 5, 1950 H. w. GRAUSAM APPARATUS FOR CASTING IIETAL 2 Sheets-Sheet 2 Filed Sept. 13, 1947 Patented Sept. 1950 APPARATUS FOR CASTING METAL Harold W. Grausam, Fords, N. J assignor to The American Metal Company Ltd., New York, N. Y., a corporation of New York Application September 13, 1947, Serial No. 773,889

3 Claims.

My present invention relates to apparatus for casting metals which, in the molten state, readily oxidize upon exposure to the air and retain resulting oxides upon solidification, with the concomitant undesirable effect upon the metal. More particularly the invention relates to apparatus for casting oxygen-free, high-conductivity copper.

In the casting of billets, bars, cakes and the like of oxygen-free, high-conductivity copper and analogous metals, various precautions are taken to insure that the resulting castings will be free from copper oxides and occluded gases which have an undesirable effect upon the metal. Various apparatuses for casting such metals are dis closed in the following United States Patents,

-viz.: 2,060,033, 2,060,034, 2,060,135 and 2,061,037.

According to one conventional method of casting metals of the character set forth, the metal is poured into a mold, mounted on an intermittently movable carrier of a multiple mold casting machine, through a strainer box which is adapted to be lowered into and raised out of substantially sealing engagement with the top of a mold with which it is held in contact during the casting operation and through which strainer box reducing gas at super-atmospheric pressure is continuously flowed until the casting has cooled and solidified to the extent that it will not be readily attacked by the oxygen from the air. This procedure requires approximately three minutes or more per casting, depending upon the size of the cake or billet being cast, and thereby materially reduces the potential efficiency of the'casting machine and renders the workers temporarily idle during the cooling and solidification period of the casting.

My present invention has for its primary object the provision of apparatus which will greatly increasethe productive capacity of a multiple mold casting machine when used in casting metals of ,the character set forth. A further object is to said opening and a duct leading to the mold mold, moving the mold out of alignment withthe strainer box and moving another mold into alignment with the strainer box and thereby enable one or more castings to cool and solidify under the protective influence of a reducing atmosphere, while permitting additional castings to be poured. The invention will be better understood from the detailed description which follows, when considered in connection with the accompanying drawings, wherein:

Figure 1 is a fractional top plan view diagrammatically illustrating the invention as applied to the molds of a rotatable casting wheel.

Fig. 2 is a section taken substantially along the plane of the broken line 22 of Fig. 1.

Fig. 3 is a top plan view of a gas seal mold cover constituting an essential part of the present invention, a part of said cover and a part of the slide gate being broken away to better illustrate the constructional details.

Fig. 4 is a section taken substantially along the plane of the line 4-4 of Fig. 3, the slide gate being omitted.

Fig. 5 is a perspective view of the slide gate used in conjunction with the mold cover.

Referring to the drawings, in the various figures of which the same referencecharacters are employed to designate corresponding parts, the,

numeral l0 indicates a mold wheel of a multiple mold casting machine having a plurality of angularly spaced, circumferentially disposed molds I l which are adapted to be successively brought into casting position under a strainer box l2 adapted that molten metal may be maintained in the furnace against contaminating oxidizing influences and may be poured therefrom through the strainer box into a mold carried by the mold wheel, while such flowing metal is being completely protected against oxidation by a reducing gas which may be continuously charged into 7 the strainer box. This general combination'per se is old.

According to the present invention, upon each of the molds ll, which are preferably of the 3 water-cooled type, is fitted a cover ll having an opening l5 therethrough, said cover also having a slide gate l6 adapted to cover and uncover said opening, as desired, and means are provided for charging reducing gas into the mold when the slide gate is closed. The cover l 4 may be of a shape to conform to the mold and as herein shown is of circular form provided with a plurality of circumferentially spaced depending lugs II for positioning the cover over a circular mold. The cover is formed from a pair of circular plates l8 and IS, the upper plate l8 being formedwith an oblong diametrical opening while the plate 59 is formed with an elongated diametrical opening 2i in underlying aligned relation to the opening 20, the plates is and i9 being herein shown as being spaced from each other by a spacing element 22 having a peripheral portion which is substantially coincident with the marginal portions of plates l8 and I9 and having a central diametrical recess 23 extending through the edge of the plate of a width somewhat greater than 'the widths of the openings 20 and 2| and disposed in alignment with said openings 20 and 2| so as to provide the through opening I5 in,the cover when the slide gate I4 is in withdrawn position. The plates l8, l9 and the element 22 may be suitably connected together in any desired manner and when so connected provide channel guides 24 for the movement of the slide gate IS in the cover. Preferably the slide gate l6 has a loose guided fit in said channel guides and may be slid into closed or open relation to the opening l5 by any means such as a rod 25 which at its inner end is secured to the plate [8 and at its outer end has an upturned gripping portion 26.

The under plate IQ of the cover is formed with a duct 21 leading from one end of the wall of the opening 2| to the outer periphery of the plate and into which duct extends the flattened end of a pipe 28, the other end of which is connected to one end of a hose or pipe 29. The other end of the pipe 29 is connected through a control valve 30 to av distributor head 3|, which, in turn, is connected through a swivel coupling joint 32 with a hose 33 leading from a source of producer gas or other reducing gas supply.

In mounting the covers on the mold an asbestos rope ring 34 is preferably used to provide a seal between the top of the mold and the under side of the cover, and a second asbestos rope ring 35 is disposed on the top face of the cover to provide a seal with the strainer box l2 when the latter is moved downwardly into superposed relation with the mold cover, preparatory to casting an ingot or billet in the mold.

The strainer box l2 here shown is merely illustrative of a type of device through which the molten metal may be flowed from a furnace or other vessel into the mold without exposing said molten metal to the oxidizing influence oi the air. a

With a mold cover l4 fitted over the top of each of the molds l l, the casting of oxygen-free, high-conductivity copper or other analogous metals will be carried out in substantially the following manner: It will be assumed that the mold l l at the time it reaches the casting station under the strainer box l2 has already received on its inner surface a coating of mold wash and that the molds are of the bottom opening type.

When a mold arrives at the casting station, thebrought down into contact with the asbestos rope packing 35 to provide a substantial seal between the strainer box and the mold cover, the slide gate IS in the cover I 4 is open, and upon opening the bottom of the mold the air in the mold cavity is completely displaced by the reducing gas flowing therethrough from the strainer box. The bottom of the mold is then closed and the furnace is tilted to pour metal through the strainer box and through the opening IS in the cover it into the mold, such pouring being controlled by viewing the flow of metal through the windows 38, 39 and 40. During this casting operation the valve 30 connecting the source of reducing gas with the pipe 29 leading to the mold space heneath the cover is open and the gas being supplied thereby and through the strainer box which escapes around the edges of the strainer box will burn due to the high temperature of the molten metal. After the mold is filled to the desired height with molten metal, the pouring is stopped, the slide gate I6 is moved inwardly to close the opening in the cover while continuing theflow of reducing gas into the mold through the duct 21 and the strainer box I2 is then raised out of engagement with the mold cover. The casting in the mold being maintained under the influence of a reducing atmosphere when the gate is closed, said mold and casting may be removed from the casting station by partially r0- tating the mold wheel and a second mold may be moved into position at the casting station and the casting operation repeated. The time re-' quired for the casting to cool to an extent that oxygen from the air will not readily attack it will depend upon the size of the casting. Hence, one or more additional castings may be poured While the first one is cooling. When a casting has cooled to the desired extent the gas supply to the mold is shut oil and the slide gate in the mold cover may be opened. By the time that a mold containing a casting has traveled about it has cooled sufiiciently to perinit the dumping of the casting into a bosh con ining water to promote the further cooling of the casting.

Whereas heretofore it had been necessary tomaintain the strainer box in position on the mold until the casting solidified sufliciently to avoid oxidatiomfrom the air, a practice which required three minutes or more, it will be appreciated that with the gas seal mold covers of the present invention the casting wheel can be used to substantially continuously castmetals of the character set forth since, as soon as a casting is poured, the slide gate in the cover may be closed and the mold removed from the casting station to cool under a non-oxidizing atmosphere. It will thus be evident that the efiiciency of the casting operation with metals of the type described may be increased to substantially the potential capacity of the multiple mold casting machine, and at the same time the efficiency of the workmen employed in the casting operations may also be brought to a higher level since their time is more fully and productively occupied.

While I have shown and described a preferrrd embodiment of the gas seal mold cover and its application to a multiple mold rotatable casting wheel, it is to be understood that changes in the details of construction of the mold cover and operative arrangement of the slide gate relative thereto may be resorted to within the range of mechanical and engineering skill without departing from the spirit of the inventionas defined in the appended claims.

What I claim is:

1. Apparatus for casting metal which in the molten state readily oxidizes upon exposure to the air, comprising a mold, a cover at the top of the mold and carried there y and a strainer box movable into and out of engagement with the cover, said cover having an opening therein through which molten metal can pass from the strainer box into the mold and packing means for providing a substantially gas-tight seal with the strainer box, a gate for closing said opening in the cover and a duct extending from the opening below the gate to the exterior of the cover.

2. Apparatus according to claim 1 wherein the strainer box is movab e substantially vertically relatively to the mold, and the gate is slidable to close the opening in the cover while the strainer box is in engagement with the cover.

3. Apparatus for casting metals which, in the molten state readily oxidize upon exposure to the air, comprising a multiple mold casting machine having a plurality of molds, a casting station to which the molds may be successively brought, a cover at the top of each mold and carried thereby, a strainer box at the casting station movable into and out of engagement with a mold cover, said cover having an opening therein through which molten metal can pass from the strainer box into the mold, a gate for closing said-opening in the cover and a duct extending from the opening below the gate adapted for connection with a source of reducing gas, whereby a mold, when charged with molten metal, may be closed off by the gate and removed from the casting station while maintaining above the metal in the mold an atmosphere of reducing gas.

HAROLD W. GRAUSAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

3. APPARATUS FOR CASTING METALS WHICH, IN THE MOLTEN STATE READILY OXIDIZE UPON EXPOSURE TO THE AIR, COMPRISING A MULTIPLE MOLD CASTING MACHINE HAVING A PLURALITY OF MOLDS, A CASTING STATION TO WHICH THE MOLDS MAY BE SUCCESSIVELY BROUGHT, A COVER AT THE TOP OF EACH MOLD AND CARRIED THEREBY, A STRAINER BOX AT THE CASTING STATION MOVABLE INTO AND OUT OF ENGAGEMENT WITH A MOLD COVER, SAID COVER HAVING AN OPENING THEREIN THROUGH WHICH MOLTEN METAL CAN PASS FROM THE STRAINER BOX INTO THE MOLD, A GATE FOR CLOSING SAID OPENING IN THE COVER AND A DUCT EXTENDING FROM THE OPENING BELOW THE GATE ADAPTED FOR CONNECTION WITH A SOURCE OF REDUCING GAS, WHEREBY A MOLD, WHEN CHARGED WITH MOLTEN METAL, MAY BE CLOSED OFF BY THE GATE AND REMOVED FROM THE CASTING STATION WHILE MAINTAINING ABOVE THE METAL IN THE MOLD AN ATMOSPHERE OF REDUCING GAS. 